We can, if we’ll just do it, stop adding as much CO2 and sequester carbon back deep underground; pyrolize biomass and store the resulting biochar. Doing this in a big way for about a century will restore the climate to a more natural state.

so that news item I linked the other day was fake then?
how bout the green cement site
something about bubbling through sea water I think http://cleantechnica.com/2008/09/02/green-cement-is-carbon-neutral-sequesters-co2-from-power-plants/

CO2 concentration was 280 ppm, in 1750 CE. W.F. Ruddiman, in his popular “Plows, Plagues and Petroleum” makes the point that there were important anthropogenic influences even than. Still, that level, or a bit higher, say 290 ppm, is a safe target; not too cold; not too hot; just right.

Humans may have been altering the climate even before that - according to an article in New Scientist on the research of William Ruddiman, http://environment.newscientist.com/channel/earth/mg19926721.600-the-ice-age-that-never-was.html which suggests that human activities 6000 years ago, such as deforestation, altered the natural ghg rhythms enough to prevent an ice age.

I suppose you could say the advent of trees and grasses disrupted the natural state of the planet and it’s pre vegetation climate and it should be returned to those natural conditions - Lets Nuke the trees!

Or you could say Humans are nature. We don’t disrupt nature, we are nature.

And who said that 290 ppm was some king of optimum?
For Most of history it was much higher.
Anything below 1000ppm is fairly unusual for planet earth.
We are simply at a very low point in CO2 concentration and it shows by the reduced vegitation we have now.

I’m thinking an ice free Antarctica might be interesting and a wide open North would be great. Dead frozen useles tundra is paradise to some but not me.

Sure we’d lose the current coastlines, but who cares about that? They’re just lined with a bunch of ugly cities anyway. Unfortunately this global warming thing is going to take a long time.

What about the Bears - who cares? they’ll adapt, they’ll move - and if they eventually die out? once again who cares? it happens. Species die out when they don’t belong in the biosphere anymore.

What about water crises? It’s here now - lots of people are without good water supply. Haven’t you heard of river blindness? As long as people fight wars and make boundaries the poor will suffer. Don’t think that there is a magic CO2 atmosphere content that is going to prevent the poor from suffering and dying. It’s not about climate. It’s about war and nationalism and the heart of man. It can’t be fixed by chemistry.

But historically those changes have happened over millions of years. Here we’re talking significant changes over the course of a human lifespan. Most organisms on the planet can only adapt to environmental change by natural selection, which is slow, so if those changes happen too fast it will result in a mass extinction.

Oh, and don’t forget hundreds of millions of refugees from rising oceans, flooding and drought. Consider the magnitude of your rationalization if you say you’re ok with that.

David, ever wondered how the large sauropods managed to find enough vegitation to eat? We know what elephants do, sauropods where several times bigger eaters.

Elevated CO2 levels. 3-4 TIMES today’s levels, at least. Plants grew much faster because of that, hence enough to support super large dinosaurs.

We are at a CO2 low in all of geologic history right now. This started 55myo when India started to collide with Asia. The rising Himalayas altered wind patterns that normally went into Siberia. Rain fall on the Himalayas started instead (hence the Gobi Desert). That increased rainfall took CO2 out of the atmosphere which in turn disolved the uplifting rock, sequestering the CO2 as carbonate rock (the largest single source of CO2 is locked up in the world’s carbonate rock)

Humans are a cold adapted species and won’t do well in a warmer world. In the entire time of the existance of Homo sapiens, the only time with a significantly higher temperature than now was during the Eemian interglacial (when CO2 was 287 ppm, maximum). At that time East Africa, mankind’s original home, suffered serious prolonged droughts; our remote ancesors were thereby forced out of their Eden to spread, eventually, to all lands.

In 1850 CE, wiuth CO2 at 288 ppm, the Swiss glaciers stopped growing. By 1958 CE, with CO2 at 315 ppm, the Swiss glaciers were in retreat at 4 m/y. So about 290 ppm seems to be a sensible amount to aim for.

David.
Respectfully!! Really?
“Humans are a cold adapted species and won’t do well in a warmer world”

Humans live comfortably in tropical cliamtes and arctic cliamtes. (more comfortably in the tropics)
The temperature range is more than 30 degrees C.

Even full on nutbars like James Hansen are claiming less than 3 degrees increase (reality says 1)People won’t even notice it.

And as for the glaciers, geeze!!! Nost of the melting happened before the magic 1950 switch over form natural warming to man made warming.
They have been melting quite naturally since the mid 1800s.
Nothing new here…. move along! move along!

I think since the warming effect of CO2 is pretty much tapped out already, a target level of 700 to 1000 would be very advantageous for agriculture and world food supply.

long before a global warming of 6 K. For the effects thereof, read Mark Lynas’s “Six Degrees” or Joe Romm’s “Hell and High Water”.

The pre-industrial level of CO2 was 280 ppm in 1750 CE. By 1850 CE it reached 288 ppm. This small change was enough so that the glaciers started melting. (And many people depend upon glaciers for a reliable source of water.)

There are many effects to a warmer world than just the temperature. As I said, people won’t prosper in a wamer world.

Now don’t get all sarcastic on me. For the record, I don’t use a spell checker. They are unreliable, usually American, and if your spelling error results in a real word (but not the one you meant), it doesn’t notice that it’s wrong for the context. And also for the record, hoarde is how the verb is spelt. Check it out.

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